Improvement in safety-stop tor watches



s'. CURTIS SMITTL-or BoSToN, MASSACHUSETTS.

Letters Patent No. 99,117, dated January 25, 1870.

IMPROVEMBNT IN SAFETY-STOP FOR WATCHES.

The Schedule referred to in these Letters Patent and making part of the same.

To all to whom these pyesents shall come Be it known that I, S. C Un'rrs SMITH, of Boston,

in the county of Suffolk, and Commonwealth of Massachusetts, have made an invention of a new and useful Improvement in \Vatches,or other time-keepers; and do hereby declare the following to be a full, clear, and exact description thereof, d'ue reference being had to '-the accompanying drawings, making part of this specitication, and in which- Figure l is a vertical section of the barrel, pillarplate, and stop-works plate of a watch containing my l invention or improvement.

Figure 2is a horizontal section of the barrel, and of the mechanism connected therewith, which constivtute my invention.

Figure 3, an under-side view of the barrel.'

Figure 4 is a view of the barrel, showing the modification of my invention.. 1

This invention relates to means for insuring the safety of the train of a watch or time-keeper, provided with a going-barrel, whose motive-power is a coiled spring, should a fracture of such spring occur' while in a contracted state. A

I am aware that various devicesto accomplish this purpose have been heretofore invented and patented. In all of these cases, however, a strain and concussion come upon the train, at the breaking of the spring,

before such spring has time to react and recoilupon itself and upon the compensating-device, and it is at this instant of time, that the harm, if any, often occurs.

The object of thisinvention is to guard against'harm to the train, byentirely preventing any movement of the barrel and main gear, upon fracture ofthe spring, and by this means, allow the spring to recoil upon itself, and spend its force in this way, which would otherwise be exerted upon the tra-in, at the moment of breakage.

My invention consists in xing to any convenient part of the barrel of the watch, an annular ratchet, and

' in' pivoting to one ofthe plates, below the head of such barrel, in immediate proximity to the barrel, a springpawl or click, this pawl taking into the teeth of the ratchet, and permitting it to travel but in one direction only, and that, the one aected by the power of the main-spring. f

In the drawings accompanying this specification, and which illustrate my invention- A denotes the pillar-plate, and b, the stop-works plate of a watch containing a. gdingebarrel, this barrel being shown at' c, and its main gear-wheel at d,

these parts being arranged in manner similar to ordinary watches of its class.

1n carrying out my invention, I. affix to the under or outer-face of the barrel-head, and immediately below the main gear, an annular ratchet, e, while, to the pillar-plate of the watch, I. pivot a spring-pawl, f, in such manner that it shall take into the teeth of the ratchet, 'as represented in fig. l of the drawings.

It will, of course, be at once apparent that the adopl tion of this ratchet and pawl permit of rotation of the barrel 'but in one direction, this direction, as before observed, being that in which it is forced to travel by the distension of the main-spring. t

Should a fracture of the main-spring take place, the spring-pawl acts to instantlyarrest any movement of the barrel in a reverse direction; consequently the force of the recoil of the spring is spent upon itself, and the entire immunity of the main or other gears of the train from its action, is secured, whereas, in other devices, before the inertia, consequent upon the recoil of the spring, can be' changed from itself to the barrel, it is spent for an instant upon the train.

This ratchet and pawl occupies no valuable space'in l a watch-movement, while its extreme simplicity 'and eciency will at once recommend it to watch-makers, to whom this specification is chiefly addressed.

I do'not contiue myselfto the locality of the ratchet, as herein illustrated, as it will be evident that this locality may be varied, without violating the spirit of my invention, which is intended to embrace the applica'- tion, to the barrel and plate of a watch, of van annular ratchet and`a stop-paw', in such manner as to'operate as before explained. l

The ratchets, for instance, may be applied to the under side or face of the barrel-head, as shown in iig. 4 of the drawings, the spring-pawl being pivote'd tothe pillar-plate and below the barrel.

What I claim, and desire to secure by Letters Pat# \'1t, is`

l The combination, with the goingbarre1 of a watch or other time-piece, o f an annular ratchet fixed to or moving in unison withsaid barrel, and a spring-pawl attached to the piilar-plate, and operating in connection with said ratchet, substantially as and for the pur poses shown and described.

' S. CURTIS SMITH.

Witnesses:

EDWARD GRTFFITH, FRED. CURTIS. 

